Javascript 将变量从php文件发送到jquery文件

我试图将php文件中的php变量传递到单独的JavaScript文件。我试图将输入函数中php文件末尾的变量传递到名为

$message

和

$username

的jQuery变量中

以下是我目前的情况：

chat.php

<?php
    //form data
    $username = $_POST['username'];
    $password = $_POST['password'];
    //sql server connection credentials
    $servername = "localhost";
    $serverusername = "suser11";
    $serverpassword = "suser11";
    $databasename = "chat_database";
    // Create connection
    $conn = new mysqli($servername, $serverusername, $serverpassword, $databasename);
    // Check connection
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    }
    echo "Connected successfully<br /><br />";
    $username = $conn->real_escape_string($username);
    $password = $conn->real_escape_string($password);
    $sql = "SELECT Salt FROM users WHERE Username='$username'";
    $result = $conn->query($sql);
    while($row = $result->fetch_assoc()) {
        $salt = $row["Salt"];
    }
    $sql = "SELECT * FROM users WHERE Username='$username' AND Password=MD5('$password$salt')";
    $result = $conn->query($sql);
    if($result->num_rows === 0) {
        $conn->close(); //close the db connection
        header('Location: login.html'); //redirect to login.html
    } else {
        // output data of each row
        while($row = $result->fetch_assoc()) {
            echo "UserID: " . $row["user_id"]. " - Name: " . $row["username"]. "<br />";
        }
    }
    // Close the database connection
    $conn->close();
?>
<textarea id="myChat" type="text" style="width:500px; height:500px;"></textarea>
<br/>
<br/>
<input id="myText" name="myText"/>
<input type="hidden" value="<?php echo $username; ?>"/>
<button id="add">
    <b>Add to chat</b>
</button>
</body>
</html>

在php中，您可以像这样传递：
只需替换您的代码：

// output data of each row
        while($row = $result->fetch_assoc()) {
            echo "UserID: " . $row["user_id"]. " - Name: " . $row["username"]. "<br />";
        }

在ajax中：

$.ajax({ 
       type: "POST",
       url:'myprocess.php',
       data:{'xml': $xmlString},
       dataType:'text/xml',
       success: function(data){ 
              details = data.split("||");
              username = details[0];
              password = details[1];
       }
});

我在哪里包括php？在我当前php代码的末尾，由于某种原因，它仍然不起作用。我是否也打算用上面的代码替换当前的ajax？这就是我尝试过的，但没有成功。
while($row = $result->fetch_assoc()) {
   echo $row["user_id"]."||".$row["username"];
}

$.ajax({ 
       type: "POST",
       url:'myprocess.php',
       data:{'xml': $xmlString},
       dataType:'text/xml',
       success: function(data){ 
              details = data.split("||");
              username = details[0];
              password = details[1];
       }
});